DE10 2005 049 663 A1 discloses an electromagnet with a cylindrical hollow magnet body which includes a yoke, a pole core with an opposite armature element that influences the characteristic curve and a housing, and a cylindrical coil and a cylindrical armature with a support rod and an armature piston that is movably arranged relative to the pole.
In an electromagnet the armature piston is supported axially movable in a support tube or a support sleeve, wherein the support tube or the support sleeve terminates at an end within the pole core or within the armature opposing element of the pole core and extends at another end beyond the yoke, in particular to the transversal wall of the housing and includes the sleeve base at this end in case it is configure as a support sleeve. The pole core or its armature opposing element which is penetrated by the support rod closes the housing.